Battery Replacement - Economy Method

[vertex]

I've seen a lot of threads about battery problems. Most of us know that the Prius has 2 size batteries, depending on if you have the SMKS or not. My car has the SMKS. My car's battery was nearly dead. If I turned on the headlights for 30 seconds, the battery voltage would drop so much, that the car would no longer start. On the other hand, if you just parked it, it would last a week or more before needing a jump.
After having a dead battery twice in one week I had enough. The physical size of the battery is smaller then most auto batteries. I stopped my my local auto supply store, and they had no batteries in stock that were narrow enought to fit. (See Hobbits post on changing batteries, it is excellent.) I thought I should be able to get a battery for much less then the dealer price, or changing to a yellow top. Looking around the store more, I noticed lawn tractor batteries. The largest one they had was the correct width, but a couple of inches smaller in height and an inch smaller in length. The price was also very appealing, $35. Well, being a cheapskate, I figured with 330 CCA capacity, it had to be adequate and alot better then the battery I was using. I purchased the Exide GT-X group U1 battery. Pictures of the battery, and it installed in the car are attached. In the installed picture, you can see a strap I had to make to connect the + connector to the post. I cut two 2" long 3/4 diameter pieces of PVC pipe to use as spacers to hold the battery down between the battery hold down clamp and the battery. you can see one of them in the picture next to the danger label. I used the old negative cable, and opened up the ring clamp, and used the existing hardware to attach it to the negative post. (I removed the red cover for the picture.)
It has been in for a week, and is working fine. If you need a new battery, and are stuck, these seem to be readily available, and will work. Or, if you want to save a buck, give it a try.

[usbseawolf2000]

Thanks! Keep us posted how it goes.

I have 2006 model too and my 12V lead acid battery is still doing fine. I may need to replace it in 2 years.

Did you see the CCA rating on the OEM battery? I am wondering if it is also around 330.

[djasonw]

Excellent job! Reminds me of the way I cut corners when I owned a Cessna 152. I needed a new alternator and anything for a plane is five times what it would cost if it were for a car. Anyway, I bought a rebuilt Ford alternator and it worked fine.

I changed the 12V battery in my 2004 last summer. My friend assisted (and did most of the work) and he did a great job. I bought it online from a Toyota dealer and paid $104 incl shipping. Your price sounds a lot better! It will be interesting to see how it holds up. I see no reason why it won't last just as long since the specifications are virtually the same. Good luck!!

[vertex]

I don't think the factory battery has a CCA rating. The car doesn't have a "starter" motor that sucks current, so it doesn't need one. The CCA of the yellow top battery Hobbit used is 450. I'll take a closer look at it before I return it for the core exchange. The ratings are definetly not the same, but is is 12 volts, and the discharge current on the battery is quite low when the car is off, I measured under 50 ma. That is 1.2 AH per a day. At that rate the battery will hold up a few weeks, same as the factory battery. The only real need for capacity on this battery, I think, is for reserve is the car won't turn on, and you need to run the emergency flashers. I suspect it won't last quite as long under those conditions. Otherwise, it should be fine. I think the AH is 34, so 34/1.2= 25+ days before the battery needs a charge. The yellow top battery that Hobbit used is rated at 38, so, I'll take 34 for the much lower cost.

[Patrick Wong]

All good, except that it appears the battery is the traditional liquid acid type instead of AGM (absorbent glass mat); and it probably does not have a vent attachment leading to a rubber hose like the original equipment battery. If your right rear fender gets nailed in an accident, you may have liquid acid all over the luggage compartment or worse. During normal operation, hydrogen gas is being produced by the traditional 12V battery and is just being vented into the hatch space, lacking attachment to a rubber hose that leads to the fender.

For owners who are not satisfied with buying a replacement Toyota battery, I suggest that you should look for a battery that is 1) AGM and 2) equipped with a vent attachment. Beyond those considerations, the AH rating should be in the mid-30s minimum, and of course the physical dimensions must fit the available space.

vertex pointed out a couple of reasons why the 12V battery must have a reasonable capacity. Another reason is if your inverter dies while you are traveling at speed. The 12V battery has to provide enough energy so that you can gracefully come to a stop and shut down the vehicle.

[krousdb]

I just replaced mine with the elearn Optima Yellow Top which is rated at 38Ah, 575 CA and 450 CCA.

[vertex]

Patrick:
If you look at the factory battery, it has liquid sloshing around inside, so I don't think there is a disadvantage over the factory battery. The yellow top is certainly a better battery. You won't get much Hydrogen out, unless you are using water, and need to top off the battery. When that happens, its time for a new battery with the Exide. As I said, I'm not recommending this for everyone, but if you understand the tradeoffs, you can make a decision that works for you. Last year, my Ion needed a battery. I went and picked one up at my local parts store. When I put it in, I found the same thing with the vents, the OEM battery had them, the new one did not. It is in the trunk on the ION. Anyway, I think the risk is minimal, both from acid leakage and from hydrogen explosions.As a manufacturer, you have to vent for liability issues.

[northwichita]

Quote from another site concerning AGM batteries
Deep Cycle Battery FAQ

AGM batteries have several advantages over both gelled and flooded, at about the same cost as gelled:

Since all the electrolyte (acid) is contained in the glass mats, they cannot spill, even if broken. This also means that since they are non-hazardous, the shipping costs are lower. In addition, since there is no liquid to freeze and expand, they are practically immune from freezing damage.
Nearly all AGM batteries are "recombinant" - what that means is that the Oxygen and Hydrogen recombine INSIDE the battery. These use gas phase transfer of oxygen to the negative plates to recombine them back into water while charging and prevent the loss of water through electrolysis. The recombining is typically 99+% efficient, so almost no water is lost.
The charging voltages are the same as for any standard battery - no need for any special adjustments or problems with incompatible chargers or charge controls. And, since the internal resistance is extremely low, there is almost no heating of the battery even under heavy charge and discharge currents. The Concorde (and most AGM) batteries have no charge or discharge current limits.
AGM's have a very low self-discharge - from 1% to 3% per month is usual. This means that they can sit in storage for much longer periods without charging than standard batteries. The Concorde batteries can be almost fully recharged (95% or better) even after 30 days of being totally discharged.
AGM's do not have any liquid to spill, and even under severe overcharge conditions hydrogen emission is far below the 4% max specified for aircraft and enclosed spaces. The plates in AGM's are tightly packed and rigidly mounted, and will withstand shock and vibration better than any standard battery.


Their greater efficiency generally leads to longer life another big positive . There are alternative AGM batteries that I'll look at when the time comes to replace mine.

[Patrick Wong]

Originally Posted by vertex

...If you look at the factory battery, it has liquid sloshing around inside, so I don't think there is a disadvantage over the factory battery...

Yes, some other owners have also reported this. I personally find this to be quite fascinating because I examined the original equipment batteries in my 2001 and 2004 and they both were AGM and "dry", no liquid sloshing around inside. The Toyota New Car Features manual points out that the 12V battery is AGM and must not be replaced by a different type.

Yet, some other owners reported similar findings as you. Their batteries are also made by GS and look exactly the same as my battery, yet they are different inside...

[vertex]

Originally Posted by Patrick Wong

Yes, some other owners have also reported this. I personally find this to be quite fascinating because I examined the original equipment batteries in my 2001 and 2004 and they both were AGM and "dry", no liquid sloshing around inside. The Toyota New Car Features manual points out that the 12V battery is AGM and must not be replaced by a different type.

Yet, some other owners reported similar findings as you. Their batteries are also made by GS and look exactly the same as my battery, yet they are different inside...

My car had the GS S36B24 battery. Can't find any specs on it.